To the best of my knowledge, linear trackers also have a non-zero (if constant) tracking angle since the cartridge has to drag the tonearm along. One would hope that those of the better kind used some kind of servo (à la power steering) to minimize both force and tracking angle, otherwise I'd imagine bearing friction would be extremely critical.

I'm awfully grateful for digital technology, that's for sure. It takes so many ifs and buts out of the equation it's not even funny. Just compare where a $150 record player and $150 CD player are on their respective diminishing returns scales in terms of output quality - absolutely no contest. Not to mention $50 DAPs and soundcards...

... To the best of my knowledge, linear trackers also have a non-zero (if constant) tracking angle since the cartridge has to drag the tonearm along. One would hope that those of the better kind used some kind of servo (à la power steering) to minimize both force and tracking angle, otherwise I'd imagine bearing friction would be extremely critical. ...

Many non-servo linear trackers use an air bearing (air is blown into the gap between the sleeve the tonearm is attached to, and the rod it slides on.) The arm platform has to be very precisely leveled, and the arm wires have to be carefully dressed (see the wires in the posted picture). For a good example of a servo powered integrated arm and turntable, consider the Technics SL-10 and SL-15.